Surface Extrude: sheets from open curves and profile walls (#815)

surface.extrude sweeps open curve chains and profile boundaries along the sketch normal into a surface body (walls only, no caps). Saved under format 17.

Refs #757

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/doc/src/assembly.rs

@@ -321,6 +321,7 @@ impl FeatureKind {
             }
             FeatureKind::Revolve { .. }
             | FeatureKind::Extrude { .. }
+            | FeatureKind::SurfaceExtrude { .. }
             | FeatureKind::Combine { .. }
             | FeatureKind::Loft { .. }
             | FeatureKind::Sweep { .. }